One problem that has been encountered in the operation of such a continuous extrusion apparatus is that of controlling and handling in a satisfactory and safe manner the unwanted extrusion of metal (called "flash" in the trade) near the outlet end of said passageway through the gaps which provide the necessary working clearances between the side walls of the said groove and the cooperating, opposing surfaces of the said shoe member portion which projects radially into said groove. That extrusion if not properly controlled can produce continuous compacted waste strips of metal of very substantial cross-section and strength. Such waste strips have been found to be both difficult and somewhat dangerous to control and handle. Moreover, the apparatus has needed to be shut down so as to enable the flash to be removed by shearing or even hack-sawing.
When a split wheel member is used the unwanted extrusion of such waste strips can impose forces which tend to force the two wheel member portions apart and so widen the said gaps through which that unwanted extrusion takes place, which widening in turn leads to increases in the thickness of the said waste strips, and which welding ultimately leads, if the growth of the flash is not properly controlled, to damage of the said wheel member and/or said shoe member.
Furthermore, the increased frictional drag exerted on said wheel member by the waste extruded metal present in the said clearance gaps requires an increase in the torque for driving the wheel member, and adds to the heat generated by friction and the operating temperatures of the various parts of the cooperating wheel and shoe members.
In addition, the size of said waste strips and the difficulty of handling them necessitates the quite frequent stopping of the apparatus for the purpose of removing those strips, since they cannot be safely handled and removed while the apparatus is in operation.